constructor no longer accepts logger, emit statistics events instead

[squeep-mystery-box] / lib / mystery-box.js

diff --git a/lib/mystery-box.js b/lib/mystery-box.js
index abef55c474a619a273e68e932f793058d05ff853..5dcf1b1fe4dbc8486c62de6e0cf3cbd3be96f2a6 100644 (file)
--- a/lib/mystery-box.js
+++ b/lib/mystery-box.js
@@ -1,13 +1,18 @@
 'use strict';
 
+const { EventEmitter } = require('events');
 const crypto = require('crypto');
 const zlib = require('zlib');
 const { promisify } = require('util');
 const common = require('./common');
 const allVersions = require('./version-parameters');
 const { performance } = require('perf_hooks');
+const { name: packageName, version: packageVersion } = require('../package.json');
 
-const _fileScope = common.fileScope(__filename);
+const packageInfo = {
+  packageName,
+  packageVersion,
+};
 
 const brotliCompressAsync = promisify(zlib.brotliCompress);
 const brotliDecompressAsync = promisify(zlib.brotliDecompress);
@@ -58,17 +63,14 @@ const payloadFlagsMask = (availableFlags.BufferPayload);
 const payloadFlagsShift = 7;
 
 
-class MysteryBox {
+class MysteryBox extends EventEmitter {
   /**
-   * @param {Console} logger
    * @param {Object} options
    * @param {String|String[]} options.encryptionSecret - if an array, will always encrypt with first secret, will attempt to decrypt with all; useful for rolling secrets
    * @param {Number=} options.defaultFlags
    */
-  constructor(logger, options = {}) {
-    this.logger = logger;
-    this.options = options;
-
+  constructor(options = {}, ...args) {
+    super(...args);
     this.secrets = common.ensureArray(options.encryptionSecret);
     if (!this.secrets.length) {
       throw new Error('missing encryption secret');
@@ -257,6 +259,32 @@ class MysteryBox {
   }
 
 
+  /**
+   * Stats tracked when packing/unpacking boxes.
+   * @returns {Object}
+   */
+  static _newStats(method) {
+    return {
+      stats: {
+        method,
+        version: undefined,
+        flags: undefined,
+        flagsRaw: undefined,
+        serializedBytes: undefined,
+        compressedBytes: undefined,
+      },
+      timingsMs: {
+        start: performance.now(),
+        preCompress: 0,
+        postCompress: 0,
+        preCrypt: 0,
+        postCrypt: 0,
+        end: 0,
+      },
+    };
+  }
+
+
   /**
    * Put contents into a mysterious box.
    * @param {Object|Buffer} contents
@@ -265,27 +293,14 @@ class MysteryBox {
    * @returns {String}
    */
   async pack(contents, version = this.bestVersion, flags = this.defaultFlags) {
-    const _scope = _fileScope('pack');
-    const timingsMs = {
-      start: performance.now(),
-      preCompress: 0,
-      postCompress: 0,
-      preCrypt: 0,
-      postCrypt: 0,
-      end: 0,
-    };
-    const stats = {
-      version,
-      flags: undefined,
-      serializedBytes: undefined, // original contents size in bytes
-      compressedBytes: undefined, // compressed contents size in bytes
-    };
+    const { stats, timingsMs } = MysteryBox._newStats('pack');
 
     if (!(version in this.versionParameters)) {
       throw new RangeError(`MysteryBox format version ${version} not supported`);
     }
     // eslint-disable-next-line security/detect-object-injection
     const v = this.versionParameters[version];
+    stats.version = version;
 
     const { compression, payloadIsBuffer } = MysteryBox._decodeFlags(flags);
 
@@ -342,6 +357,7 @@ class MysteryBox {
 
     const flagsBuffer = Buffer.alloc(v.flagsBytes);
     flagsBuffer.writeUInt8(flags, 0);
+    stats.flagsRaw = flags;
     stats.flags = this._prettyFlags(flags);
 
     // Authenticate all this data
@@ -359,7 +375,7 @@ class MysteryBox {
     const result = Buffer.concat([versionBuffer, flagsBuffer, iv, salt, tag, encrypted, final]).toString('base64url');
     timingsMs.end = timingsMs.postCrypt = performance.now();
 
-    this.logger.debug(_scope, 'statistics', { ...stats, ...MysteryBox._timingsLog(timingsMs) });
+    this.emit('statistics', { ...stats, ...MysteryBox._timingsLog(timingsMs), ...packageInfo });
 
     return result;
   }
@@ -371,15 +387,7 @@ class MysteryBox {
    * @returns {Object}
    */
   async unpack(box) {
-    const _scope = _fileScope('unpack');
-    const timingsMs = {
-      start: performance.now(),
-      preCompress: 0,
-      postCompress: 0,
-      preCrypt: 0,
-      postCrypt: 0,
-      end: 0,
-    };
+    const { stats, timingsMs } = MysteryBox._newStats('unpack');
 
     if (!box) {
       throw new RangeError('nothing to unpack');
@@ -399,6 +407,7 @@ class MysteryBox {
       throw new Error('internal inconsistency, mismatched version byte length');
     }
     offset += v.versionBytes;
+    stats.version = version;
 
     const minBytes = v.versionBytes + v.flagsBytes + v.ivBytes + v.saltBytes + v.tagBytes;
     if (raw.length < minBytes) {
@@ -407,6 +416,7 @@ class MysteryBox {
 
     const flags = raw.subarray(offset, offset + v.flagsBytes).readUInt8(0);
     offset += v.flagsBytes;
+    stats.flagsRaw = flags;
 
     const { compression, payloadIsBuffer } = MysteryBox._decodeFlags(flags);
 
@@ -461,12 +471,17 @@ class MysteryBox {
         break;
     }
     timingsMs.end = timingsMs.postCompress = performance.now();
+    stats.serializedBytes = payload.byteLength;
+    if (compression) {
+      stats.compressedBytes = decrypted.byteLength;
+    }
 
     if (!payloadIsBuffer) {
       payload = JSON.parse(payload.toString('utf8'));
     }
 
-    this.logger.debug(_scope, 'statistics', { version, flags: this._prettyFlags(flags), ...MysteryBox._timingsLog(timingsMs) });
+    stats.flags = this._prettyFlags(flags);
+    this.emit('statistics', { ...stats, ...MysteryBox._timingsLog(timingsMs), ...packageInfo });
 
     return payload;
   }
@@ -504,7 +519,4 @@ class MysteryBox {
 
 }
 
-// Expose for stubbing in tests
-MysteryBox._test = { crypto };
-
 module.exports = MysteryBox;
\ No newline at end of file